Pilot burner apparatus



june 2,1936. G. A. TUCK 2,042,688

PILOT BURNER APPARATUS 'A Filed April l,` 1935 6;@ Orge Tuck ATTORNEY.

Patented June 2, 1936 UNITED STATES ATENT OFFICE Claims.

This invention relates generally to burner equipment for household heating furnaces, floor furnaces, water heaters, and like appliances, which are supplied with natural or artificial fuel 5 gas. It is concerned primarily with apparatus utilizing a temperature-responsive element, whereby the supply of gas to the main burner is interrupted if the pilot burner becomes extinguished.

In apparatus of the above character it has been common in the past to utilize a bimetallic strip or like temperature-responsive element, which is associated with the pilot burner and which transmits motion to a gas control valve.

l5 In some gas appliances, as for example Water heaters, the valve may directly control gas supplied to a main burner, while in other appliances the valve may vcontrol an auxiliary shut-off valve which in turn controls gas supplied to the main burner. In constructions of the prior art, the control valve, which is operated by flexing of the bimetallic element, requires a packing about its operating member, to avoid leakage of gasl to the atmosphere. Such a packing gland causes operating difficulties, in that if it is sufficiently tight to avoid leakage to the atmosphere, the forces required for proper operation are of such magnitude as to place unduey strain upon the bimetallic element, withv the result that operation 30 may be unreliable or the bimetallic element may take a permanent deformation and thus require frequent adjustment or replacement.

It is an object of the present invention to afford an apparatus of the above character in which the necessity of providing a packing gland about the operating member of the control valve is obviated, thereby enabling the bimetallic element to perform its functions in a reliable fashion, with operating forces of relatively small magnitude.

A further object of the invention is to provide an assembly, including a pilot burner and thermostatic control means, which is relatively com- -pact and whichv can be placed as a unit directly in the combustion chamber of a gas appliance. 45 Additional objects of the'invention will' appear from the following description in which certain embodiments of the inventionV have been set forth in detail inv conjunction with the accompanying drawing.

50 Referring to the drawing:

Fig. 1 is a side elevational view, in cross-section, illustrating a device incorporating the present invention.

Fig. 2 is a plan view of the device shown in 55 Fig. l.

(Cl. 15S-117.1)

Referring first to Figs. l and 2, the device illustrated consists of a body I0, which can be in the form of a suitable casting. Openings and I2 are provided in this body, for connection with the pipes or tubes I3 and I4. Secured to the body III, and forming in effect a part of the same, there is a fitting I6 which in turn carries a pilot burner tip I'I. The opening I I, with which tube I3 connects, communicates with a chamber |8 formed in the body I0 and which will hereinafter be referred to as a gas admission chamber. The port I2 communicates with a space or chamber I 9, which is separated from chamber I8 by the valve seat 2 I.

Fitting I6 is also formed to afford a chamberA 22, in which fuel gas supplied to the burner tip II is intermixed with combustion-supporting air. This chamber is in communication with the eX- ternal atmosphere through a side opening 23, and is separated from the chamber I8 by the wall 24. As illustrated, wall 24 is in the form of a plug, having threaded connections with the body I0 and the fitting I6, and therefore serving to connect these parts together. Wall 24 is provided with a small plug 2G, which is drilled to afford a restricted orifice 2'II of fixed dimensions. In order that the size of this orifice may not vary with changes in temperature, it is desirable to form the plug 26 of a metal or metal alloy having a negligible coefficient of temperature expansion, as for example invar.

To provide a suitable valve member for cooperating with seat 2|, a metal ball 28 is provided in the chamber I8, and this ball is attached to the lower end of an operating rod or wire 29. The wall 24 is provided with an opening 3|, through which the rod 29 slidably extends. Since opening 3| affords a certain amount of clearance around rod 29 to facilitate substantially frictionless raising and lowering of the rod to effect opening and closing movements of ball 28, a certain amount of gas leakage will occur from chamber I8 to the chamber 22, through the clearance so afforded, in addition to flow of gas through the restricted orifice 2l. In order that ball 28 may rest with the proper amount of pressure upon its seat 2|, a suitable lfollower weight 83 is provided. This follower weight has a central opening 34 to accommodate rod 29, and is adapted to normally rest upon the upper side of the ball' 28.

In order to effect raising and lowering move-y ments of rod 29 by externally applied forces, a lever 36 is provided. This lever extends ,through the opening 23 and is carried lby a ful- 2 e crum pin 31. Its inner end is attached to the upper end of rod 29, whereby when the lever is rotated in a clockwise direction as viewed in Fig. 1, the ball 28 is raised from its seat.

Operating forces are applied to the exterior end of operating lever 36 by thermostatic means, which can be described as followsz-Secured to the body I0 there is an extension bracket 38. Attached to the upstanding portion 39 of this bracket, there is a bimetallic strip 4I. The free end of this strip terminates in proximity with the burner tip I1. The discharge orifice from tip I1 has been shown in the form of a slot 42 which, on"v that side of the tip adjacent the, free Vend of strip 4I, delivers a part of its flame on the underside of the strip to afford rapidheatingfof the same when the strip is cool.

Disposed below the bimetallicstrip 4lthere1isV a weighted lever 44, one end of which hasn a pivotal connection 46 to the bracket 38. The free end of bimetallic strip 4I is provided with a slot 41, to loosely accommodate a screw 48. The lower end of the screw is shown havingV an adjustable threaded connection with a plate 49, which in turn is attached to the free end of lever 44. Beneath plate 49, lever 44 is provided with a shoulder or ledge 5I, which is adapted to engage the exterior end of lever 36.

In a typical installation, the device described above is mounted in close proximity to a main burner 52, which is to be ignited by a ilame from the pilot burner tip I1. To facilitate such an installation, the body IIJ is shown provided with a bracket 53, which can be attached to the main burner or to some other part of the heating appliance which may be conveniently afforded.

Operation of the device described above can now be explained as followsz-Pipe I3 is connected to a source of gas supply, while pipe I4 is connected to supply gas to the main burner 52. Assuming that the pilot burner is in operation, the ilame from the burner tip serves to maintain the bimetallic strip 4I at an elevated temperature, so that this strip is flexed downwardly to substantiallythe position indicated by the dotted lines in-Fig.1. The weighted lever 44 will also assume a lowered position, as indicated by dotted lines, to maintain the exterior end of lever 36 depressed and to maintain ball 28 elevated with respect to its seat. Thus, under such conditions, gas is free to iiow past the Valve ball 28 and through pipe I4-to the main burner. Likewise, since lever 44 is resting upon lever 36, there is no strain upon the bimetallic strip. Assuming now that the pilot iiame becomes extinguished during periods when the main burner 52 is not in use, bimetallic strip 4I cools and flexes upwardly to raise the weighted lever 44. Raising of lever 44 is accompanied by counterclockwise movement of lever 36, as Viewed in Fig. l, to drop the valve ball 28 on its seat 2l. Thereafter no further gas can be supplied to the main burner, until the device is recycled by again igniting flame issuing from the burner tip I1, to reheat the bimetallic strip 4I.

A particularly novel feature of the device described above is that leakage past the rod 29 is received within the mixing chamber 22, from whence it is conveyed as part of the combustible mixture of gas and air to the burner tip I1. This feature makes possible the absence of any packing about rod 29, and the absence of packing makes possible substantially frictionless operation. Thus, only small predetermined forces need be applied tothe outer end of lever 36, such as 'are aiorded by lowering the weighted lever 44.

A further feature of the invention is that the strain placed upon bimetallic strip 4I is never in excess of the amount of force required to lift lever 44. Therefore the bimetallio strip is never stressed beyond its elastic limit, and it will not 5 mitting members leading to remote controlling devices need bc employed.

- Irclaim:

l. In pilot burner apparatus, a gas iiow control valve having a projecting operating member about which gas leakage can occur, means forming a chamber entirely enclosing the projecting portion of the operating member, the chamber serving to receive the gas leakage, a burner tip 25 communicating with said chamber, an air admission port communicating between the outer atmosphere and the interior of the chamber, an actuating member connected to the projecting end of the operating member within said cham- 30 ber, and extending through said opening to the exterior of the chamber, and temperature-reresponsive means heated by the flame of the burner tip for operating the actuating member.

2. In pilot burner apparatus of the character described, a body forming a chamber for mixing air with fuel gas, a. pilot burner tip communicating with the chamber, one wall of said chamber having an orifice for admitting fuel gas and an` other wall of the chamber having an opening for admitting combustion-supporting air, a gas iiow control valve member, an operating member connected to said valve member and slidably extending through said one wall and terminated with said mixing chamber, an actuating lever connected to the inner end of the operating member and extending through said opening to the exterior of the body, and temperature-responsive means for operating said actuating member, said temperature-responsive means being located ex- 50. teriorly of said body.

3. In pilot burner apparatus of the character described, a hollow body having an inner wallY serving to divide the interior of the body into a gas admission chamber anda gas mixing cham- 55 ber, a movable valve member located in the gas admission chamber, a valve operating member having its one end connected to the valve member and being slidably extending through an aperture in said wall whereby leakage of gas may occur through said aperture into the gas mixing chamber, the other end of said member being disposed and enclosed within the gas mixing chamber, an air admission opening in the body leading from the exterior atmosphere to the mixing chamber, a pivotally mounted actuating lever connected to Ythe inner end ofthe operating member and extending to the exterior of the body through the air admission opening, an auxiliary orifice serving to admit gas from the gas admission chamber to the gas mixing chamber, a burner tip communicating with the mixing chamber, and temperature-responsive mechanism located exteriorly of the body for operating said actuating member, said temperature-responsive icl means including a bimetallic strip disposed to be heated by the ame of the burner tip.

4. In pilot burner apparatus of the character described, a hollow body having an inner wall serving to divide the interior of the body into a gas admission chamber and a gas mixing chamber, a burner tip communicating with the mixing chamber, a movable Valve member in the gas admission chamber, an air admission opening in the body leading from the exterior atmosphere to the mixing chamber, an actuating member eX- tending through said opening from the exterior of the body to the mixing chamber, a reciprocable operating member connecting the valve member with the inner end of the actuating member, said operating member being entirely enclosed by the body, there being an opening in the wall' to loosely accommodate the operating member whereby gas leakage occurs from the admission chamber to the mixing chamber about said operating member, an auxiliary orifice serving to establish communication between the gas admission chamber and the gas mixing chamber, and temperatureresponsive means located exteriorly of the body for applying moving forces to the outer end of the actuating member, said temperature-responsive means including a bimetallic strip disposed to be heated by the flame from the burner tip.

5. In pilot burner apparatus of the character described, a pilot burner, valve means for controlling flow of gas to the pilot burner, an actuating member adapted to be moved in a vertical direction to eiect operation of said valve means, and temperature responsive means for applying motion to said actuating member, said temperature responsive means including a bimetallic strip disposed to be heated by the flame from the burner, means forming a fixed support for one end of said strip, a weighted lever arranged to engage the actuating member to move the same in one direction, and means forming a lost motion connection between the free end of the bimetallic strip and the free end of the weighted lever, whereby when 20 said bimetallic strip is permitted to cool, it serves to lift said Weighted lever.

GEORGE A. TUCK. 

